As the last week of the Winter Olympics begins, it’s clear that a lot of people are tuning in to watch live streams of the games on their tablets, smartphones and computers, instead of waiting until primetime to watch tape-delayed events.

The 2012 Olympics in London marked the first year NBC offered live event streaming on the Web, and Sochi has continued a transition from primetime TV coverage of the games to constant, multi-platform presentation of the action.

The network is offering 539 hours of television coverage and more than 1,000 hours of live-streamed online coverage of the Winter Olympics this year.

The live-streaming alone eclipses the entirety of NBC’s coverage of the 2010 games in Vancouver, which included 436 hours.

Live streams are available on NBCOlympics.com and on the network’s mobile app to users who can demonstrate they are paying customers of cable TV.

After the first week of the games, NBC officials announced that its three main Web and mobile properties, NBCOlympics.com, NBC Sports Live app and a results app– had drawn 30 million unique visitors. That was up 54 percent from the 2010 Vancouver Winter Olympics, when NBC did not offer live streamed video.

NBC Sports Group Chairman Mark Lazarus said the practice of live viewing is part of a larger shift in the model of live sports coverage, from watching on television to using online streams that require authenticated cable subscriptions to view.

“We are moving towards a time when all of our sports, and all sports in general, are going to be authenticated in the very near future,” Lazarus said in a recent conference call. “We believe in it and are fully supporting the model, and it’s critical to who we are.”

Additionally, primetime viewership is up for the games, according to an NBC news release.

NBC is offering its television coverage on several of its subsidiary networks, including NBC Sports, CNBC and USA.

For example, the night the network aired American snowboarder Shaun White’s fourth-place finish on the men’s halfpipe, it raked in 23.7 million viewers, up 17 percent from the same night four years ago in Vancouver, according to a news release.

Lazarus said in a release before the Olympics that he wasn’t concerned with advertising revenue to fill all the network’s media, saying NBC has received more than $800 million in ad money for the Olympics this year as the network has moved further into a multi-platform model.

“Where families gather, advertisers follow,” he said. “And our ad sales are at an all-time record for the Winter Games.”

And in addition to using Internet services to show the Olympics, the network is also using social media to direct its audience toward the games, research and media development president Alan Wurtzel said.

“What’s interesting is that 86 percent of Twitter users who saw any TV-related tweet the last few days saw at least one about the Olympics,” he said. “This is a brand-new metric. It hasn’t been around very long … but I think you’ll agree, those are really impressive numbers.”

While NBC continues to work to tap social media potential, the officials said viral content coming from the games is also grabbing viewers.